Pressure-medium actuated shifting arrangement

ABSTRACT

Pressure-medium actuated shifting arrangement for a gear transmission, primarily for a multispeed transmission, in which the speed selection lever performs a movement in accordance with a double H shifting configuration. Within the reach of the driver, in a shift console another transmission shaft is mounted, which is displaced by the speed selection lever for path selection and twisted for gear shifting. The transmission shaft has also cams and valves cooperating with a pressure-medium source over the selection cylinder and shift cylinder mounted to the gear box which actuate a gear-shift-lever shaft, whereby not only the desired shift couplings are put into effect, but also feedback information about the shifting situation in the transmission perceptible by the driver is conveyed. Further safety valves are mounted on the gear-shift-lever shaft which allow the selection movement to take place only in the neutral position and multistep cams are located on the same shaft, which together with 3/2-way valves mounted radially displaceable as pistons arrest the two-position shift cylinder also in the median position. Over the piston assembly an optimal gear or an optimal path, in dependence from the travel parameters, for instance the speed of the vehicle, is offered to the driver for shifting.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a national phase application corresponding toNo. PCT/EP84/00195 based, in turn, on a Europatent application No.EP83/00216 also filed as a PCT application on Aug. 12, 1983.

FIELD OF THE INVENTION

The invention relates to a shifting arrangement for a gear transmission,particularly a multispeed transmission, wherein the speed selectionlever follows a movement in accordance within a double H shiftingconfiguration and is mounted with the reach of the driver in a shiftingconsole, wherein a transmission shaft is displaced for path selectionand is twisted for gear shifting and with means to control valves whichdirect the pressure medium from a pressure-medium source to each of theselection cylinder mounted on the gear box for path selection and to theshift cylinder for gear shifting, whereby the shifting arrangement alsohas locking means and devices for perceptible feedback informationthrough which a gear-shifting is prevented when the coupling is stillclosed and the driver is advised through the speed selection lever aboutthe shift position of the transmission at the moment.

BACKGROUND OF THE INVENTION

In such a shifting arrangement, the path selection takes place through adisplacement of the speed selection lever transversely to the directionof travel and the gear shifting forwards and backwards with respect tothe travel direction.

In a shifting console mounted within the reach of the driver alltransmission functions needed to shift a transmission are establishedand are transmitted via a pressure medium to the selection- and shiftingcylinders mounted on the gearing and acting upon the gear-shift-levershaft.

Depending on the type of the gear transmission, for instance maintransmission only or a main transmission in combination with anauxiliary transmission, or a multispeed transmission with torque pathsplitting, the demands on such a shifting arangement are very high,since not only must the desired shifting be transmitted via a pressuremedium, but also as known in a mechanically shifted gear box, it isnecessary to provide feedback information, recognizable by the driverregarding the shifting status in the gear box itself.

Such an arrangement in the form of a pneumatical shifting arrangement isknown from British Pat. No. 1 179 426, and has a shifting console with aspeed selection lever shiftable in the gear-shifting gate with a doubleH shifting pattern for eight forward speeds and one reverse speed. Theshift locks act upon the manual shift lever depending upon the positionof the clutch via two locking cylinders and a rocker shaft and thefeedback about the selected path is mechanically released at theshifting cylinder via pilot valves.

Such arrangements can no longer satisfy the requirements of a shiftingarrangement in a modern transmission, which needs for the transmissionof the selection and shifting alone a large number of conduitconnections and are cumbersome from the point of view of manufacturingand tuning.

OBJECT OF THE INVENTION

It is therefore the object of the present invention to provide animproved shifting arrangement and to simplify its construction andservice.

SUMMARY OF THE INVENTION

This object is attained in accordance with the invention by providingthat the selection and shifting motions are transmitted over each of acouple of three-port, two position (3/2) valves mounted on the shiftingconsole and cooperating with cams on the transmission shaft to each of athree-position selection cylinder and two-position shifting cylindermounted on the gear transmission, whereby the 3/2 valves are mountednext to each other in axial direction for path selection and incircumferential direction for gear selection. In the supply conduitsbetween each of the 3/2 valves and the three-position selection cylindera safety valve cooperating with the gear-shift-lever shaft and open forpassage only in neutral position is mounted. In each of the two conduitsfor the two-position shifting cylinder a 3/2 valve cooperating with thecams on the gear-shift-lever shaft is mounted in such way as tofacilitate the arresting of the two-position shifting cylinder in amedian position.

Due to the mounting of a transmission shaft and of 3/2 valvescooperating therewith in the shifting console within the reach of thedriver it is possible to transmit to pressure mediums in a relativelysimple manner the desired signals for the intended shiftings, whereby abasically known gear-shift-lever shaft is displaced at the gear box inan equally simple manner over selection- and shifting cylinders. Due tothis arrangement, it is also possible to incorporate in a simple waysafety devices for the path selection. It is particularly advantageousthrough a skillful arrangement of the 3/2 valves and the cams on thetransmission shaft to convert the five paths of the double H shiftingsarrangement to the three paths needed in the main gear box over athree-position selection cylinder, so that the gear-shift-lever shaftrequires only one shift finger for the shifting of the gear shift bars.Also, the arrangement of the 3/2 valves on the transmission shaft andthe gear-shift lever shaft is advantageous. In connection with the 3/2valves acting displaceably like positions and each of them cooperatingwith a cam on the gear-shift-lever shaft it is possible to achieve notonly a feedback that can be sensed by the driver, but also the use of asimple two-position shifting cylinder for the three shift positions.

Advantageously, the two 3/2 valves cooperating with the gear-shift-levershaft and built as displaceable pistons are axially displaceable mountedeach in a bore, are pressed each by a compression spring radiallytowards the outside and are moved radially towards the inside, againstthe pressure of the spring and towards the cams by the pressure mediumpassing through the other 3/2 valve. The cams on the gear-shift-levershaft corresponding to the 3/2 valves can have multiple steps and in theneutral position N both contact elements can rest against the transitionsection between the each of the inner radial cam sections and the medianradial sections of the cam.

The construction in which the 3/2-ways valves are built as radiallydisplaceable pistons in cooperation each with a multistep cam running incircumferential direction on the shift-lever shaft is, considering theperformed functions, simple in design and also simple to produce.

The pressure pick-up, when between the two supply conduits to thetwo-position shifting cylinder an additional two-way valve is mounted,which directs the pressure medium to a piston assembly located on thespeed selection lever, the piston assembly blocking the lever in theshifting position until the shifting in the gear box is finished.Between the 3/2-way valves and the two-position shifting cylindertogether with the piston arrangement makes it possible to recognize in asimple way in the shift console the end of synchronization and theperformed speed selection. With only two 3/2 valves and a cam extendingcircumferentially on the transmission shaft cooperating therewith it ispossible, when the two 3/2-way valves are mounted next to each other incircumferential direction on the transmission shaft and are open forpassage only in the neutral position N of the gear-selection lever andwhen in the respective shifting positions and end positions only thecorresponding 3/2 valve cuts off the pressure medium to translate intocontrol pressure at the lever position indicator the relativelycomplicated displacement of the gear-shift-lever shaft and the threeshift positions as well as the synchronization point familiar to thedriver like in a purely mechanical shifting arrangement.

According to another feature of the invention in spite of thedisplacement of the transmission shaft in the paths according to thedouble H shifting pattern the gear-shift-lever shaft is displaced at thegear transmission by a three-position selection cylinder only in thethree paths of the main transmission, whereby for the selection of themedian path both piston chambers are pressure-medium actuated. Thethree-position selection cylinder consists of a housing and a three-partpiston whereby the inner piston is rigidly connected with thegear-shift-lever shaft and has axially in the center a collar of alarger diameter limiting two piston bushings mounted axiallydisplaceable on the inner piston blocking each in one displacementdirection. The bushings are also prevented from moving each in onedisplacement direction by a stop ring fastened to the housing and thatin the median position, the collar and the stop cover each other inaxial direction and that both frontal sides from the inner piston to thefrontal housing limit have respectively th same intervals as theintervals between the paths on the gear-shift-lever shaft. Thisspeed-selection arrangement realizes in a simple way the selectionfunctions and the three-position cylinder has, except for the stop ring,only a smooth, not recessed bore.

Two additional 3/2 valves can be mounted on the transmission shaft closeto each other in axial direction for interconnecting the auxiliarytransmission via an auxiliary shifting cylinder. An additional shiftlever for the shift pilot valve of the splitter group is mounted on thespeed selection lever which connects the split transmission via a splitshifting cylinder. Between the pressure-medium source and the pilotvalves in the shift console an additional 3/2 valve is provided which isin passage position only when it is opened by manual coupling actuation.

This construction of the pressure-medium actuated shift is particularlysuited for a multispeed transmission, because the auxiliary transmissionin a double H shifting configuration and the shifting of the split groupcan be carried out in the usual manner with a shift lever on the speedselection lever. In transmissions with the known coupling actuation viafor instance a foot pedal, a 3/2-way valve is connected in a simplemanner to this actuating means, so that the pressure medium fordisplacement is available only when the coupling is open. A converterbridging coupling can be carried out depending on the pressure existingin the control block after the two-way valve. Thereby the known pressureswitch can be eliminated in a WSK-(converter shifting coupling) steeringmechanism so that the pressure conduit for the piston assembly at thespeed-selection lever is utilized for a second function withsimultaneous elimination of the switch valve between the source of thepressure medium and the 3/2-way valve. Finally, it is possible to mountin a simple way in the shift console another piston assembly cooperatingwith the transmission shaft over an entraining pin, whereby thisarrangement, especially in a multiple transmission, provides the drivernot only with optimal operation conditions of the gear box, but alsofacilitates the shifting as a consequence of the possiblity to establishin each case the right speed selection, so that the driver can betterconcentrate on the operation of his vehicle and is no longer undulydistracted.

BRIEF DESCRIPTION OF THE DRAWING

Further details of the invention are clarified with reference to theaccompanying drawing.

The drawing shows:

FIG. 1 the shift console with speed selection lever and the 3/2-wayvalves mounted on the transmission shaft, in schematic representation.

FIG. 1A the devices mounted on the gear transmission especially in thearea of the gear-shift-lever shaft, in a schematic representation.

FIG. 2 a gear transmission as a multispeed transmission with thearrangements for speed selection, schematically represented.

FIG. 3 a gear transmission according to FIG. 2 in another view.

FIG. 4 a control diagram for the piston arrangement in the shiftconsole.

FIG. 5 a table of the connected switch valves, with reference to theavailable speeds.

FIG. 6 shift console with speed selection lever in partial section.

FIG. 7 shift console according to FIG. 6--a view in the traveldirection.

FIG. 8 shift console with piston arrangement, topview and section.

FIG. 9 shifting configuration with locking gate and representation ofpower thresholds in the shifting- and selection direction.

FIG. 10 diagram of speed of rotation.

SPECIFIC DESCRIPTION

In FIG. 1 a shift console 1, mounted in the driver's compartment of forinstance a motor vehicle, with the speed selection-lever 2 of thetransmission shaft 3 and all 3/2 valves actuated by the transmissionshaft is represented. The 3/2-way valves on the transmission shaft aresupplied via a main pressure duct 42 with a pressure medium for instanceair from a pressure medium source 4 over a switch valve 41 when a geartransmission 5 is utilized with a main clutch actuated via a clutchpedal by the driver, the supply occuring only then when the clutch isopen. The transmission shaft 3, in the case of a multispeed transmissionis displaced over the speed-selection lever 2 in for instance fiveselection positions or parts 31--and in three shift positions--neutral;paths 1, 3, 5, 7; paths R, 2, 4, 6, 8--directly rotationally staggeredaccording to the double H shifting configuration. Through the speedselection movement, the two 3/2 valves 11, 12 located next to each otherare displaced by the cam 32 extending in axial direction of thetransmission shaft 3 in such a way that the conduits I and II are eitheractivated by the pressure medium or devoid of it, as follows:

    ______________________________________                                        Path position  Conduit I                                                                              Conduit II                                            ______________________________________                                        R              X        --                                                    1/2            X        X                                                     3/4            --       X                                                     5/6            X        X                                                     7/8            --       X                                                     ______________________________________                                         X signifies that the conduit is effective.                               

When passing from the paths 3/4 to 5/6 or vice versa, the alternateswitching of the 3/2 valves 13, 14 for the switching of the auxiliarygear box 52 over the conduits VI and VII and the auxiliary switchingcylinder 55 (FIG. 1A) occurs over a further cam 33. On the transmissionshaft 3 in circumferential direction two further 3/2 valves 15, 16 arelocated, which are actuated by a cam 34 for the speed selection in suchmanner that in the neutral position N of the speed-selection lever 2both 3/2 valves 15, 16 are open and the conduits IV and V leading to thecontrol block 7 are actuated by the pressure medium. A locking cylinder43 is also connected to the main pressure conduit which prevents adisplacement of the transmission 3 and thereby of the speed-selectionlever 2 in the direction of shifting rotation, whenever the mainpressure conduit 42 is emptied of air. In connection with the shiftingmotion, an additional piston assembly 21 is mounted at thespeed-selection lever 2, which is always actuated by pressure mediumover the conduit III during a shifting cycle and thereby facilitates thedisplacement of the speed-selection lever 2 only to the shiftingposition 22, 23--stop of the respective piston 24 at the housing 17 ofthe shift console 1--. Only when the shifting in the main transmission51 is completed and there is no lower pressure in the conduit III, thespeed-selection lever 2 can be brought in the correspondingspeed-selection end position 25, 26. If the gear transmission has, likein this case, also a split group 53 it is possible to connect also thisgroup-- see conduit VIII--over the shift lever 27, the splitter-groupshifter valve at and in the speed-selection lever 2.

The conduits I to VIII lead directly, respectively over the couplingdevices to the assemblies mounted on gear transmission 5, which areshown in FIG. 1A.

Conduit I leads to a piston chamber of a three-position selectioncylinder 6, for instance a left one 61, and conduit II leads to theother piston chamber, the right-hand 62, whereby in both conduits asafety valve 91 is mounted in addition. These act together with thegear-shift-lever shaft 9 and are passable only in the neutral positionthereof, so that an axial displacement--in the selection direction--ofthe lever shaft 9 at the gear transmission 5 is possible only in thisposition.

The three-position selection cylinder 6 comprises a housing 63 an innerpiston 64 rigidly connected with the gear-shift-lever shaft and havinghalfway axially a collar with a larger diameter 640. Two identicalpiston bushings 65 are arranged to the left and the right of this collarso that they rest against it and are of equal length with the innerpiston. In the median position--as represented--on both sides of theinner piston 64 and the piston bushings 65, the piston chambers 61, 62are frontally arranged, their axial extensions corresponding each to apath interval between the patches 1/2 to R and 1/2 and 3/4, consideredon the lever shaft 9.

In the bore with the same diameter in the housing 63 a stop ring 66having the same width as the collar 640 is mounted at the inner piston64 axially in the middle and limits the piston bushings 65 in theiraxial displacement. The free space resulting 67 resulting between thestop ring and the collar is always devoid of air.

The three-position cylinder works as follows:

In the median position--path 1/2 in the main gear box 51--the switchfinger of the gear-shift-lever shaft 9 engages in the connecting rodconnected with the rocker arm for the speed-selection coupling 1/2. Bothpiston chamber 61, 62 are filled and the median position is establishedover the piston bushings 65 in connection with the stop ring 66. Thisshifting situation occurs when the transmission shaft 3 is in the paths1/2 and 5/6--see table--. When the piston chamber 62 is emptied ofair--path R in the transmission cylinder 3--the inner piston 64 moves tothe right until it reaches the stop, whereby the collar 640 entrains theright piston bushing 65R. The gear-shift-lever shaft 9 is in theposition of path R.

If in the median position the air is evacuated from the left pistonchamber 61, the inner piston is pushed to the left by the pressure inpiston chamber 62 until it reaches the stop, whereby the collar 640entrains the left piston bushing 65L. This shifting situationcorresponds to a path position of the transmission shaft of paths 3/4and 7/8 and the gear-shift-lever shaft 9 is in the path 3/4 of the maintransmission. From the five pathes of the transmission shaft 3 the threepaths of the main transmission 51 are reached over the three-positioncylinder 6 in connection with the cam 32 and both 3/2 valves 11, 12.

The control block 7 consists of the gear-shift-lever shaft 9 on whichtwo multistep cams 93, 94 running circumferentially are provided, eachcooperating with one radially displaceable 3/2 valve 73, 74, each ofthem located in a bore 75 in the housing 76 and each being pressedradially outwardly by a spring 77. Due to the completely displaced3/2-way valves 73, 74 the conduits IV and IVA and V and VA are connectedin a first shifting position to the two-position cylinder 8 or shut offin a second shifting position, while the conduits IVa and Va are emptiedof air between the control block and the two-position selectioncylinder. The piston chambers 71, 72 of the 3/2-way valves 73, 74working as pistons are each interconnected with the conduits leading tothe other 3/2-way valves (V with 71 over VB; IV with 72 over IVB). Afurther two-way valve 79 is connected to the conduits IVA and VA whoseoutlet, the conduit III, as described, supplies with pressure medium thepiston assembly 21 (FIG. 1)

The two-position cylinder 8 has a piston 81, two piston chambers 82, 83as well as dampers 84 working in both end positions, shifting thegear-shift-lever shaft 9 by means of a switch lever 92 in the directionof the runs 1, 3, 5, 7, respectively R, 2, 4, 6, 8 and also in neutralposition.

The control block 7 in connection with the two-position cylinder 8 worksas follows:

In the neutral position of the speed selection lever 2, the cam 34running circumferentially on the transmission shaft 3 opens for passagethe 3/2 valves 15, 16 so that the conduits IV and V are under pressure.Over the conduits VB the piston chamber 71 and over the conduit IVB thepiston chamber 72 are pressurized and both 3/2-way valves 73, 74 actingas pistons are displaced against the pressure of spring 77 in a firstinterior position, as shown. The contact pins 78 of both 3/2-way valvesare in an unsteady position between the respective interior sections ofthe cam 93A, 94A and the cam sections 93B, 94B, so that in the slightlypendular position of the contact pins 78 in connection with thegear-shift-lever shaft both 3/2-way valves can be alternately opened forpassage and this way, over the conduits IVA and VA and the pistonchambers 82, 83 the piston 81 can be held in a median position and overthe switch lever 92 the gear-shift-lever shaft can be fixed in themarked neutral position. In case of a displacement of the speedselection lever 2 in a switching position 23 corresponding to the gearsR, 2, 4, 6,8 the conduit V is emptied of air and via the 3/2-way valve73 and the conduits IV and IVA, only the piston chamber 82 is furtherpressurized so that the piston 81 moves to the right-hand end position,whereby the gear-shift-lever shaft 9 is twisted clockwise around theswitch lever 92. At the same time, over the shift finger not shown inthe drawing the shifter rod, the rocking arm and the shift sleevepertaining to the path are synchronized and connected for synchronousrun. The piston 81 is now in an end position. During this operation, thepressure supply to the piston chamber 82 via the 3/2 valve 73 isensured, although the contact pin 78 rides against the cam section 93B,because due to the depressurization of the piston chamber 71 this3/2-way valve takes a second radially outward position. Only after theshifting is performed, when the piston 81 reaches its end position, thepiston chamber 82 is also depressurized, due to the action of the camsection 93C via the 3/2 valve. This way the conduit III is alsodepressurized and the piston assembly 21 releases the shift lever, sothat it can be shifted in the gear end position.

The driver is going now to reactivate the coupling, whereby the pilotvalve 41 cuts off the pressure-medium supply. In the case of atransmission without a coupling pedal, the activation of the couplingtakes place directly via the conduit III and 80, and the pilot valve 41can be eliminated. At the two-position shift cylinder a hydraulicend-position damping device 84 of the generally known type is mounted,the action of this device being described in detail for instance in theHERION HANDBOOK No. 1, Edition 1969, pages 44-46.

The FIGS. 2 and 3 show the gear transmission 5 in a frontal view and atop view, with for instance the main transmission 51 having four gears,the auxiliary transmission 52 and the split transmission 53. In the areaof the gear-shift-lever shaft 9, the two-position shift cylinder 8 withthe damping device 84 are mounted, for the purpose of the shiftingthereof-shift lever 92. The control block is also mounted laterally onthe gear-shift-lever shaft 9 in its median area, while thethree-position shift cylinder 6 is mounted as an extension of thegear-shift-lever shaft 9. The shift cylinders 55, 56 for the auxiliarytransmission 52 and the split transmission 53, are as known, mountedclose to the drive shaft 59, a tachometer, primarily an electronictachometer 57 being also mounted in its vicinity. A coupling K or clutchconnected with the engine as is also show.

FIG. 4 shows the control diagram for the shift console 1 with thetransmission shaft 3 with an indication of the axial displacement by ahalf path (one speed), so that to each drive gear corresponds to oneposition of this transmission shaft 3. The piston assembly 170 consistsof three pistons 171, 172, 173 and three piston chambers 174, 175,176and is constructed so that these positions of the transmission shaft arereached over the entrainment bolt 178 and the locking gate 132 (FIGS. 8and 9). Pilot valves 18A, 18B, 18C correspond to the piston chambers andsupply them or empty them of air. A pressure-medium source is marked 4and the pilot valves are controlled, for instance based on the number ofrotations, from an electronic block 19. The return of the pistons 171,172, 173 takes place via a return spring 177, resting against theconsole housing 17. Between the entrainment bolt 178 fastened in thepiston 173 and the transmission shaft 3 another spring mechanism 35 ismounted.

In the table shown in FIG. 5 each of the pilot valves 18A, 18B, 18C setin supply position can be recognized, these valves leading to thedisplacement of the transmission shaft 3 in the half-pathes of gears 1to 8. The reverse speed is identified at G.R. 1 the forward speeds atG.2 to G.8 and the open pressurizing valves 18A-18C by a "1" in therespective box while the closed venting valve for the resective speed isshown by a "0". FIGS. 6, 7 and 8 show one of the possible embodiments ofa shift console 1. The gear-selection lever 2 is swingable around thecenter point of the transmission shaft 3 in the direction of the shiftpositions 22, 23 and in the gear end positions 25 and 26 of the gears,thereby twisting the transmission shaft 3 from the marked neutralposition at an equal angle (FIG. 6). The selection of path takes placedue to the rotation around the center point of a ball bearing 28 mountedon the speed selection lever and cooperates with a guide in the housing17 of the shift console 1. When the speed selection lever 2 is actuatedtransversally to the direction of travel for the path selection, whichas known, is possible only in the neutral position--the transmissionshaft 3 is displaced in opposite direction over a forked joint (pin offorked joint 133, fork 29, pin 29A). Thereby, each path, as known in anH- or double H shifting arrangement, corresponds to one deflection ofthe gear-selection lever 2 in a selection position 330, while whendeparting from these known swiching arrangements a gear corresponds toeach path (FIG. 4). Another shift lever 27 is mounted on thegear-selection lever 2 for a reversal of the transmission from aperformance-oriented layout of speed progression to aneconomically-oriented one, whereby over a shift cylinder 56 forinstance, a group connected in series (split group) is interposed. Anonrotatable jacket 134 is also mounted on the transmission shaft 3(FIG. 8), but this jacket is displaceable in each direction by a halfpath (=one gear) whereby the median position is reached without stressvia a spring mechanism 131. In the jacket 134 another locking gate 132is located, the entraining bolt 178 rigidly connected with the piston173. This locking gate 132 is so shaped that only one gear can beselected departing from the neutral position to the shift position underthe action of the shifting force, respectively either of the gears 1,3,5. . . or the gears R, 2,4 . . . and that after the force of the springmechanism 134 has been overcome in the selection direction also the twoadjacent gears become connectable, and in the case of high-levelshifting, after overcoming the force of the return spring 177, alsofurther gears are connectable.

Shifting back for more than one speed is not possible because themovement of the transmission shaft 3 in this direction is hindered bythe fact that the jacket 134 presses strongly against the frontal stop135 on the transmission shaft 3, as well as by the pistons 171, 172, 173in connection with a possible pressurization of the piston chambers 174,175, 176 which would prevent such a movement due to the connection overthe entrainment bolt 178.

The strokes 179A, B and C corresponding respectively to the pistons 171,172, 173 when under pressure, are limited by the stops 180 and are sodimensioned that the biggest is four times and the medium is twice asbig as the smallest stroke (binary coding).

The power levels--rest restoring forces do not correspond directly tothe pathes in the shifting configuration, double H shiftingconfiguration 190 (FIG. 9), as it is known to be the case (in GermanUtility Model No. 78 92 241, FIG. 3) so that the driver can sense theindividual path in the entire configuration, but these forces arerelated to the respective position of the locking gate 132 and aredisplaced within the shifting configuration in accordance with the axialdisplacement of the locking gate. In the area of the neutral positionthe locking gate is offset and and covers two half pathes so one of thehalves, for instance 132A is covered simultaneously with the half path,for instance from the neutral position to gear 3, while the second halfpath 132B extends from the neutral position to the gear position 4, butoffset by half a path and thereby, for instance, lies between gear 4 andgear 2. These two halves, 132A and 132B of the locking gate 132correspond also to the stop- and restoring forces 191, 192 so that, forinstance in the represented position of the locking gate 132, in orderto engage gear 3 no selection forces in axial direction are necessary.

As generally known, only when displacing the speed selection lever 2from the neutral position 20 in a shifting position 22, 23 and after forinstance the synchron is reached in the end positions 25,26 selectionforces to overcome the force threshold 400 and the synchronizing forceare required. But, for instance, if in this position of the locking gate132 the gears 4, respectively 2, have to be engaged then also the firstpower thresholds 310 effective in both directions have to be overcome bythe selection forces. The locking gate 132 is thereby displaced by ahalf a path in both shifting situations, which is made possible by thespring 131 between the jacket 134 and the transmission shaft 3 (FIG. 8).While in the ase of intended and accepted high-gear shiftings furtherforce thresholds are to be overcome by corresponding selection forces, afurther reverse shifting from the position locking gate 132 isprevented, because during shifting in high gear the restoring spring 177can be overpressured, while in reverse shift direction the movement ofthe jacket 134 as well as of the transmission shaft 3 is arrested by thepiston assembly. The axial displacement of the locking gate 132 takesplace over the pressure supply dependent on the number of rotations tothe piston chambers 174 to 176, in accordance with the table of FIG. 5,through the pilot valves 18A to 18C, which are switched in accordancewith the number of rotations by orders received from an electronic block19 (FIG. 4).

In the situation of FIG. 9, gear 3 is recommended to the driver forshifting, whereby he does not even have to recognize the same, since heonly has to perceive in which direction--travel or countertravel--thelowest shifting resistance is present. In the normal situation, thedriver does not select one of eight speeds, but only one of two speeds.In addition, he has the possibility, as already described, to select thetwo adjacent gears 2 and 4, although by applying bigger forces. With theshift lever 27, the driver can connect in the known manner in additionthe split group of the transmission, so that he also has the choicebetween an economy-oriented or a performance-oriented run. As can beseen from the simplified course diagram of FIG. 10, in the case of theperformance-oriented run compared with the economy-oriented run, theswitch points are displaced towards higher rotational speeds.

We claim:
 1. In a multispeed transmission of a vehicle having in ashifting console a speed-selection lever having a speed-selection levershaft and displaceable in a double-H pattern by a driver of the vehicle,a transmission shaft shiftable in response to said lever for pathselection and gear shifting, respective control valves responsive todisplacement of said shaft, transmission-operating cylinders connectedwith said valves and receiving a pressure medium upon operation of saidvalves by said transmission shaft, a clutch connected with saidtransmission, and feedback means for transmitting to said driver throughsaid speed-selection lever a perceptible indication of instantaneousshift position of the transmission and for locking out gear-shiftingoperation while said clutch remains closed, the improvement wherein;saidtransmission shaft is provided with a plurality of cams rotatable uponrotation of said shaft by said speed-selection lever; said controlvalves include respective pairs of three-port/two-position valvesactuated by each of said cams; said control three-port/two-positionvalves are grouped in alignment parallel to an axis of said shaft forselective actuation for path selection and in circumferential alignmentfor gear shifting; said cylinders include a three-position pathselection cylinder and a two-position gear-shifting cylinder connectedto said control three-port/two position valves; a respective safetyvalve is provided between the three-position path selection cylinder andeach said control three-port/two-position valve connected therewith tocooperate with said speed-selection lever shaft, said safety valve beingopen only in neutral position of said lever; and a respective furtherthree-port/two position valve is provided between said two-positiongear-shifting cylinder and each said control three-port/two positionvalve being connected therewith, said further three-port/two-positionvalves being operated by further cams on said speed-selection levershaft for arresting said two-position shifting cylinder in a medianposition.
 2. The improvement defined in claim 1 wherein said furtherthree-port/two-position valves have pistons axially displaceable in abore and urged radially outwardly by a compression spring but movableradially inwardly against the pressure of said spring and toward saidfurther cams by a pressure medium passing respectively through the otherof said further three-port/two position valves.
 3. The improvementdefined in claim 2 wherein each of said further cams has a plurality ofsteps and in said neutral position contact elements of said pistons ofsaid further valves rest upon a transition section between steps of saidfurther cams.
 4. The improvement defined in claim 3 further comprising atwo way valve between supply conduits to said two-position gear-shiftingcylinder and directing said medium to a piston assembly provided on saidspeed-selection lever, said piston assembly blocking said lever in arespective shifting position until shifting in a gear box of saidtransmission is concluded.
 5. The improvement defined in claim 1 whereintwo three-port/two position valves circumferentially in succession areconstructed and arranged to be open for flow passage only in saidneutral position of said lever and to cut off flow of the pressuremedium upon displacement of said lever into a shifting position.
 6. Theimprovement defined in claim 1 wherein said speed selection lever shaftis displaced by said three-position selection cylinder into respectivepositions corresponding to three paths of a main transmission formingpart of said multispeed transmission, two-piston chambers of saidthree-position cylinder being supplied with pressure medium for a medianpath.
 7. The improvement defined in claim 6 wherein said three-positioncylinder comprises a housing and a three-part piston having an innerpiston part rigidly connected with said speed selection lever shaft anda collar of a larger diameter defining two piston parts axiallydisplaceable on said inner piston part, each of said axiallydisplaceable piston parts being prevented from movement in onedisplacement direction by a stop ring fixed to said speed housing. 8.The improvement defined in claim 7 further comprising two additional3-port/2-position valves on said transmission shaft close to one anotheraxially of said shaft for actuating an axial transmission forming partof said multispeed transmission with said main transmission via anauxiliary shifting cylinder.
 9. The improvement defined in claim 8,further comprising a shifting valve for a splitter group where saidmultispeed transmission has a torque splitting group selection unit,said speed selection lever being provided with an additional shift leverfor operating said shifting valve.
 10. The improvement defined in claim9, further comprising yet another three-port/two position valve betweensaid control valves and a pressure medium source and permittingcommunication only upon actuation of said clutch.
 11. The improvementdefined in claim 4, wherein between said two way valve and said pistonassembly, an additional conduit is provided for effecting actuation ofsaid clutch.
 12. The improvement defined in claim 1, further comprisingan additional piston assembly in said console operable in dependenceupon a parameter of travel of the vehicle for selecting an optimal speedand path for a given travel instant selectable by the driver.